The communication channels between a transmitter and a receiver may be transmitted over a bundle of several carriers. The carriers may be combined and amplified before transmission. The power amplifier used for amplification of the transmitted signal may have a limited linear operating range. Generally, operation of a power amplifier within its linear operating range reduces the undesired inter-modulation products that may be generated in the amplifier. In order to maintain the power amplifier within its linear operating range, the peak to average ratio (PAR) of the input signal is kept at a low level. One or more method and apparatus has been disclosed in the U.S. Pat. Nos. 6,044,103, and 6,310,869, and the U.S. publication No. 2001/0038065, all incorporated by reference herein. In case of multi-carrier transmission, the PAR of the combined signal may not be controlled without substantial processing of each individual carrier signal and the combined signal. Therefore, there is a need for a method and apparatus for reducing the PAR of a combined signal in a multi-carrier transmission system.